Three-dimensional kinematics of canine hind limbs: in vivo, biplanar, high-frequency fluoroscopic analysis of four breeds during walking and trotting

Biomechanical Comparison of Three Locking Compression Plate Constructs from Three Manufacturers under Cyclic Torsional Loading in a Fracture Gap Model

OBJECTIVE

 The aim of the study was to compare the stiffness and cyclic fatigue of locking compression plate constructs from three manufacturers, DePuy Synthes (DPS), Knight Benedikt (KB), and Provet Veterinary Instrumentation (Vi), under cyclic torsion.

METHODS

 The constructs of DPS, KB, and Vi were assembled by fixing a 10-hole 3.5-mm stainless steel locking compression plate 1 mm away from a validated bone model with a fracture gap of 47 mm. The corresponding drill guides and locking screws were used. Three groups of six constructs were tested in cyclic torsion until failure.

RESULTS

 There was no significant difference in initial stiffness between DPS constructs (28.83 ± 0.84 N·m/rad) and KB constructs (28.38 ± 0.81 N·m/rad), and between KB constructs and Vi constructs (27.48 ± 0.37 N·m/rad), but the DPS constructs were significantly stiffer than the Vi constructs. The DPS constructs sustained the significantly highest number of cycles (24,833 ± 2,317 cycles) compared with KB constructs (16,167 ± 1,472 cycles) and Vi constructs (19,833 ± 4,792 cycles), but the difference between KB and Vi constructs was not significant. All constructs failed by screw damage at the shaft between the plate and the bone model.

CONCLUSION

 DPS constructs showed superior initial torsional stiffness and cyclic fatigue life than Vi constructs, whereas KB and Vi constructs shared comparable results. Further investigation is required to assess the clinical significance of these biomechanical differences.

Effect of thread direction on rotational stability in lag-screw fixation of sacroiliac luxation: An ex vivo cadaveric study in small-breed dogs

OBJECTIVE

To assess the effect of screw thread direction on rotational resistance in canine sacroiliac (SI) luxation models using left- and right-handed screws.

STUDY DESIGN

Controlled laboratory study.

SAMPLE POPULATION

Twenty-four adult canine pelves with proximal femora were examined.

METHODS

Four groups (n = 6 each) were established: right-handed screw/right SI luxation (RhRSI), right-handed screw/left SI luxation (RhLSI), left-handed screw/left SI luxation (LhLSI), and left-handed screw/right SI luxation (LhRSI). Under fluoroscopy, 2.4 mm cortical screws were placed into the SI joint in a lag fashion. An acute failure test measured force and torque at yield and peak points, with the ilium and femur positioned at a 108° angle and displacement at 0.099 cm/s. Torque (N cm) was calculated from force (N) and the moment arm (cm).

RESULTS

Differences in median torque were found at yield and peak points. RhRSI gave 50.08 N cm versus 16.01 N cm for RhLSI (p < .01), and LhLSI showed 39.42 N cm versus 19.93 N cm for LhRSI (p < .03). At peak, RhRSI recorded 67.55 N cm compared to 28.14 N cm for RhLSI (p < .01), and LhLSI reached 51.79 N cm versus 28.28 N cm for LhRSI (p < .05). All samples failed by rotation without screw breakage or fractures.

CONCLUSION

Right-handed screws provided greater rotational resistance in right-sided luxation, and left-handed screws in left-sided luxation, which demonstrated that screw thread direction influenced fixation stability in SI luxation.

CLINICAL SIGNIFICANCE

The findings suggest that selecting screw thread direction can enhance biomechanical stability in SI luxation repair, improving surgical outcomes for affected dogs.

Late acquisition of erect hindlimb posture and function in the forerunners of therian mammals

The evolutionary transition from early synapsids to therian mammals involved profound reorganization in locomotor anatomy and function, centered around a shift from "sprawled" to "erect" limb postures. When and how this functional shift was accomplished has remained difficult to decipher from the fossil record alone. Through biomechanical modeling of hindlimb force-generating performance in eight exemplar fossil synapsids, we demonstrate that the erect locomotor regime typifying modern therians did not evolve until just before crown Theria. Modeling also identifies a transient phase of increased performance in therapsids and early cynodonts, before crown mammals. Further, quantifying the global actions of major hip muscle groups indicates a protracted juxtaposition of functional redeployment and conservatism, highlighting the intricate interplay between anatomical reorganization and function across postural transitions. We infer a complex history of synapsid locomotor evolution and suggest that major evolutionary transitions between contrasting locomotor behaviors may follow highly nonlinear trajectories.

Evaluation of Meniscal Load and Load Distribution in the Sound Canine Stifle at Different Angles of Flexion

OBJECTIVES

 The aim of the study was to investigate the contact mechanics and kinematic changes in the stifle in different standing angles.

STUDY DESIGN

 We performed a biomechanical ex vivo study using pairs of canine cadaver hindlimbs. Motion sensors were fixed to the tibia and the femur for kinematic data acquisition. Pressure mapping sensors were placed between the femur and both menisci. Thirty percent bodyweight was applied to the limbs with the stifle in 125, 135, or 145 degrees of extension.

RESULTS

 Stifle flexion angle influences femoromeniscal contact mechanics significantly. The load on both menisci was significantly higher for 125 and 135 degrees in comparison to 145 degrees. Additionally, the center of force was located significantly more caudal when comparing 125 to 145 degrees in the medial meniscus as well as in both menisci combined.

CONCLUSION

 The angle of knee flexion significantly impacts the contact mechanics between the femur and the meniscus. As the knee flexes, the load on both menisci increases.

Risk Factors for Injury in Border Collies Competing in Agility Competitions

Border Collies are the most common breed in agility and their reported injury rate is much higher than that of other breeds. We aimed to identify demographic, training, and competition variables associated with the injury risk for this breed. We hypothesized that higher jump heights and competition at national/international levels would increase the injury risk. Data were collected from an internet-based survey. A logistic regression model was built using backward selection. There were 934 Border Collies in the sample, with 488 reporting an injury. The jump height relative to the shoulder height was associated with injury, with dogs jumping noticeably above or below shoulder height more likely to report a history of injury. Other identified risk factors included the number of weekends spent competing/year, the number of competitions at the national level, the age when starting elbow height jumps and backside jumps, the acquisition of the dog from a breeder, and the age of the handler. Factors associated with prolonged injury (>3-month duration) were the age when starting elbow height jumps and having a veterinary assistant as a handler. Border Collies jumping above shoulder height had an increased risk of injury. However, those jumping below shoulder height were also at a higher risk, which could have been due to reverse causality. Similarly, the observed associations regarding differences based on the number of trial weekends/year may have been impacted by reverse causality as well. The increased risk of injury with elbow height jump training at <10 months of age may indicate that the repetitive impact of jump training prior to skeletal maturity negatively influences musculoskeletal development. These data provide valuable information for further prospective studies.

Meniscal Load and Load Distribution in the Canine Stifle after Modified Tibial Tuberosity Advancement with 9 mm and 12 mm Cranialization of the Tibial Tuberosity in Different Standing Angles

OBJECTIVES

 The aim of this study was to investigate the kinetic and kinematic changes in the stifle after a modified tibial tuberosity advancement (TTA) with 9 and 12 mm cranialization of the tibial tuberosity in different standing angles.

STUDY DESIGN

 Biomechanical ex vivo study using seven unpaired canine cadaver hindlimbs. Sham TTA surgery was performed. Motion sensors were fixed to the tibia and the femur for kinematic data acquisition. Pressure mapping sensors were placed between femur and both menisci. Thirty percent body weight was applied to the limbs with the stifle in 135 or 145 degrees of extension. Each knee was tested in 135 degrees with intact cranial cruciate ligament (CCL) and deficient CCL with 12 mm cranialization of the tibial tuberosity in 135 and 145 degrees of extension. The last two tests were repeated with 9 mm.

RESULTS

 Transection of the CCL altered kinematics and kinetics. Tibial tuberosity advancement with 12 mm cranialization sufficiently restored stifle kinematics in 135 and 145 degrees but 9 mm TTA failed to do so in 135 degrees. The same effects were seen for internal rotation of the tibia. After TTA, a significant reduction in the force acting on both menisci was detected.

CONCLUSION

 Tibial tuberosity advancement could restore stifle kinematics and meniscal kinetics after transection of the CCL ex vivo in the present study. Tibial tuberosity advancement reduced the contact force ratio on both menisci significantly. No changes of peak pressure and peak pressure location occurred following TTA under any of the tested experimental settings. Increased stifle extension (145 degrees) might lead to more stability, contradictory to biomechanical theory.

Positioning of pivot points in quadrupedal locomotion: limbs global dynamics in four different dog breeds

Dogs (Canis familiaris) prefer the walk at lower speeds and the more economical trot at speeds ranging from 0.5 Fr up to 3 Fr. Important works have helped to understand these gaits at the levels of the center of mass, joint mechanics, and muscular control. However, less is known about the global dynamics for limbs and if these are gait or breed-specific. For walk and trot, we analyzed dogs' global dynamics, based on motion capture and single leg kinetic data, recorded from treadmill locomotion of French Bulldog (N = 4), Whippet (N = 5), Malinois (N = 4), and Beagle (N = 5). Dogs' pelvic and thoracic axial leg functions combined compliance with leg lengthening. Thoracic limbs were stiffer than the pelvic limbs and absorbed energy in the scapulothoracic joint. Dogs' ground reaction forces (GRF) formed two virtual pivot points (VPP) during walk and trot each. One emerged for the thoracic (fore) limbs (VPP_TL) and is roughly located above and caudally to the scapulothoracic joint. The second is located roughly above and cranially to the hip joint (VPP_PL). The positions of VPPs and the patterns of the limbs' axial and tangential projections of the GRF were gaits but not always breeds-related. When they existed, breed-related changes were mainly exposed by the French Bulldog. During trot, positions of the VPPs tended to be closer to the hip joint or the scapulothoracic joint, and variability between and within breeds lessened compared to walk. In some dogs, VPP_PL was located below the pelvis during trot. Further analyses revealed that leg length and not breed may better explain differences in the vertical position of VPP_TL or the horizontal position of VPP_PL. The vertical position of VPP_PL was only influenced by gait, while the horizontal position of VPP_TL was not breed or gait-related. Accordingly, torque profiles in the scapulothoracic joint were likely between breeds while hip torque profiles were size-related. In dogs, gait and leg length are likely the main VPPs positions' predictors. Thus, variations of VPP positions may follow a reduction of limb work. Stability issues need to be addressed in further studies.

The effect of joint orientation on passive movement of the dog's stifle

Introduction

The cranial cruciate ligament (CCL) is one of numerous structures which determine the path of the tibia relative to the femur when passively flexing/extending the stifle of the dog. The effect of cutting the CCL on passive motion with the hind limb in different orientations, is unknown. The aim of this study was to describe passive movement of the tibia relative to the femur in dogs, with the hind limb in three different orientations, and with CCL intact and cut.

Methods

Ten cadaveric hind limbs were obtained from dogs weighing between 20 kg and 25 kg and prepared for testing in a custom-built joint testing machine. Each hind limb was tested in three different orientations with data collected, using an electromagnetic tracking system, during 2 cycles of flexion/extension with the CCL intact and cut. Each cycle was initiated with the stifle in full extension (0°) and data was collected at 0°, 20°, 30°, 40°, 45°, and 55° of stifle flexion/extension.

Results

Flexion of the stifle resulted in caudal translation and internal rotation of the tibia relative to the femur, with cranial translation and external rotation occurring during extension along the identical path. Cutting the cranial cruciate ligament did not result in significant differences in translation or rotation when the stifle was orientated to approximated the standing position of a dog.

Discussion

Isometric points at the origin and insertion of the CCL can potentially be identified in CCL deficient stifles using a technique based on passive motion of an intact stifle.

Vertical ground reaction forces, paw pressure distribution, and center of pressure during heelwork in working dogs competing in obedience

Heelwork walking is a command that competitive obedience and working dogs are trained to perform. Unlike other canine sports, the research for competitive obedience sport is limited and no research regarding biomechanical gait adaptions during heelwork walking has been published. The aim of the study was to investigate the changes in vertical ground reaction forces, paw pressure distribution (PPD), and center of pressure (COP) of Belgian Malinois during heelwork walking. Ten healthy Belgian Malinois were included in the study. The dogs walked first without heeling (normal walk) and then while heeling on a pressure platform. The comparison between normal and heelwork walking was performed using mixed-effects models. Post-hoc analyses were performed using Sidak's alpha correction procedure. During heelwork walking, a significant decrease in the vertical impulse and stance phase duration (SPD) and a significant increase in the craniocaudal index and speed of COP was observed in the forelimbs compared to normal walking. At the hindlimbs, a significant increase in vertical impulse and SPD was observed during heelwork walking. Regarding PPD, a significant decrease of vertical impulse was observed at the cranial quadrants of the right forelimb and craniolateral quadrant of the left forelimb during heelwork. The area was significantly decreased at the craniolateral quadrant of the left forelimb and the time for the peak vertical force was prolonged significantly at the caudal quadrants of the right forelimb during heelwork walking. The vertical impulse was significantly increased in all quadrants of the hindlimbs except the craniolateral quadrant of the left hindlimb. The effect of these changes on the musculoskeletal system of working dogs should be investigated in further studies, using electromyography and kinematic analysis.

Estimation of skeletal kinematics in freely moving rodents

Forming a complete picture of the relationship between neural activity and skeletal kinematics requires quantification of skeletal joint biomechanics during free behavior; however, without detailed knowledge of the underlying skeletal motion, inferring limb kinematics using surface-tracking approaches is difficult, especially for animals where the relationship between the surface and underlying skeleton changes during motion. Here we developed a videography-based method enabling detailed three-dimensional kinematic quantification of an anatomically defined skeleton in untethered freely behaving rats and mice. This skeleton-based model was constrained using anatomical principles and joint motion limits and provided skeletal pose estimates for a range of body sizes, even when limbs were occluded. Model-inferred limb positions and joint kinematics during gait and gap-crossing behaviors were verified by direct measurement of either limb placement or limb kinematics using inertial measurement units. Together we show that complex decision-making behaviors can be accurately reconstructed at the level of skeletal kinematics using our anatomically constrained model.

Automatic landmark detection and mapping for 2D/3D registration with BoneNet

The 3D musculoskeletal motion of animals is of interest for various biological studies and can be derived from X-ray fluoroscopy acquisitions by means of image matching or manual landmark annotation and mapping. While the image matching method requires a robust similarity measure (intensity-based) or an expensive computation (tomographic reconstruction-based), the manual annotation method depends on the experience of operators. In this paper, we tackle these challenges by a strategic approach that consists of two building blocks: an automated 3D landmark extraction technique and a deep neural network for 2D landmarks detection. For 3D landmark extraction, we propose a technique based on the shortest voxel coordinate variance to extract the 3D landmarks from the 3D tomographic reconstruction of an object. For 2D landmark detection, we propose a customized ResNet18-based neural network, BoneNet, to automatically detect geometrical landmarks on X-ray fluoroscopy images. With a deeper network architecture in comparison to the original ResNet18 model, BoneNet can extract and propagate feature vectors for accurate 2D landmark inference. The 3D poses of the animal are then reconstructed by aligning the extracted 2D landmarks from X-ray radiographs and the corresponding 3D landmarks in a 3D object reference model. Our proposed method is validated on X-ray images, simulated from a real piglet hindlimb 3D computed tomography scan and does not require manual annotation of landmark positions. The simulation results show that BoneNet is able to accurately detect the 2D landmarks in simulated, noisy 2D X-ray images, resulting in promising rigid and articulated parameter estimations.

Fore-Aft Asymmetry Improves the Stability of Trotting in the Transverse Plane: A Modeling Study

Quadrupedal mammals have fore-aft asymmetry in their body structure, which affects their walking and running dynamics. However, the effects of asymmetry, particularly in the transverse plane, remain largely unclear. In this study, we examined the effects of fore-aft asymmetry on quadrupedal trotting in the transverse plane from a dynamic viewpoint using a simple model, which consists of two rigid bodies connected by a torsional joint with a torsional spring and four spring legs. Specifically, we introduced fore-aft asymmetry into the model by changing the physical parameters between the fore and hind parts of the model based on dogs, which have a short neck, and horses, which have a long neck. We numerically searched the periodic solutions for trotting and investigated the obtained solutions and their stability. We found that three types of periodic solutions with different foot patterns appeared that depended on the asymmetry. Additionally, the asymmetry improved gait stability. Our findings improve our understanding of gait dynamics in quadrupeds with fore-aft asymmetry.

Computational Modeling of Gluteus Medius Muscle Moment Arm in Caviomorph Rodents Reveals Ecomorphological Specializations

Vertebrate musculoskeletal locomotion is realized through lever-arm systems. The instantaneous muscle moment arm (IMMA), which is expected to be under selective pressure and thus of interest for ecomorphological studies, is a key aspect of these systems. The IMMA changes with joint motion. It’s length change is technically difficult to acquire and has not been compared in a larger phylogenetic ecomorphological framework, yet. Usually, proxies such as osteological in-levers are used instead. We used 18 species of the ecologically diverse clade of caviomorph rodents to test whether its diversity is reflected in the IMMA of the hip extensor M. gluteus medius. A large IMMA is beneficial for torque generation; a small IMMA facilitates fast joint excursion. We expected large IMMAs in scansorial species, small IMMAs in fossorial species, and somewhat intermediate IMMAs in cursorial species, depending on the relative importance of acceleration and joint angular velocity. We modeled the IMMA over the entire range of possible hip extensions and applied macroevolutionary model comparison to selected joint poses. We also obtained the osteological in-lever of the M. gluteus medius to compare it to the IMMA. At little hip extension, the IMMA was largest on average in scansorial species, while the other two lifestyles were similar. We interpret this as an emphasized need for increased hip joint torque when climbing on inclines, especially in a crouched posture. Cursorial species might benefit from fast joint excursion, but their similarity with the fossorial species is difficult to interpret and could hint at ecological similarities. At larger extension angles, cursorial species displayed the second-largest IMMAs after scansorial species. The larger IMMA optimum results in powerful hip extension which coincides with forward acceleration at late stance beneficial for climbing, jumping, and escaping predators. This might be less relevant for a fossorial lifestyle. The results of the in-lever only matched the IMMA results of larger hip extension angles, suggesting that the modeling of the IMMA provides more nuanced insights into adaptations of musculoskeletal lever-arm systems than this osteological proxy.

Objective Gait Analysis: Review and Clinical Applications

Objective kinetic and kinematic data can be used as an objective measure of treatment intervention over time but can also be used to evaluate progress of clinical patients. Force plate and pressure sensitive walkway systems both offer the clinician the ability to obtain useful kinetic data, whereas additional equipment is required to obtain kinematic data. Which system is preferred depends on what specific data the researcher or clinician hopes to acquire; both are accurate and consistent, and each offers pros and cons compared with the other that must be considered.

Patient-specific 3D-printed shelf implant for the treatment of hip dysplasia tested in an experimental animal pilot in canines

The concept of a novel patient-specific 3D-printed shelf implant should be evaluated in a relevant large animal model with hip dysplasia. Therefore, three dogs with radiographic bilateral hip dysplasia and a positive subluxation test underwent unilateral acetabular augmentation with a 3D-printed dog-specific titanium implant. The contralateral side served as control. The implants were designed on CT-based pelvic bone segmentations and extended the dysplastic acetabular rim to increase the weight bearing surface without impairing the range of motion. Outcome was assessed by clinical observation, manual subluxation testing, radiography, CT, and gait analysis from 6 weeks preoperatively until termination at 26 weeks postoperatively. Thereafter, all hip joints underwent histopathological examination. The implantation and recovery from surgery was uneventful. Clinical subluxation tests at the intervention side became negative. Imaging showed medialization of the femoral head at the intervention side and the mean (range) CE-angle increased from 94° (84°-99°) preoperative to 119° (117°-120°) postoperative. Gait analysis parameters returned to pre-operative levels after an average follow-up of 6 weeks. Histology showed a thickened synovial capsule between the implant and the femoral head without any evidence of additional damage to the articular cartilage compared to the control side. The surgical implantation of the 3D shelf was safe and feasible. The patient-specific 3D-printed shelf implants restored the femoral head coverage and stability of dysplastic hips without complications. The presented approach holds promise to treat residual hip dysplasia justifying future veterinary clinical trials to establish clinical effectiveness in a larger cohort to prepare for translation to human clinic.

A Guide to Inverse Kinematic Marker-Guided Rotoscoping using IK Solvers

X-ray Reconstruction of Moving Morphology (XROMM) permits researchers to see beneath the skin, usually to see musculoskeletal movements. These movements can be tracked and later used to provide information regarding the mechanics of movement. Here, we discuss “IK marker-guided rotoscoping”—a method that combines inverse kinematic solvers with that of traditional scientific rotoscoping methods to quickly and efficiently overlay 3D bone geometries with the X-ray shadows from XROMM data. We use a case study of three Nile crocodiles’ (Crocodylus niloticus) forelimbs and hindlimbs to evaluate this method. Within these limbs, different marker configurations were used: some configurations had six markers, others had five markers, and all forelimb data only had three markers. To evaluate IK marker-guided rotoscoping, we systematically remove markers in the six-marker configuration and then test the magnitudes of deviation in translations and rotations of the rigged setup with fewer markers versus those of the six-marker configuration. We establish that IK marker-guided rotoscoping is a suitable method for “salvaging” data that may have too few markers.

Control of Mammalian Locomotion by Somatosensory Feedback

When animals walk overground, mechanical stimuli activate various receptors located in muscles, joints, and skin. Afferents from these mechanoreceptors project to neuronal networks controlling locomotion in the spinal cord and brain. The dynamic interactions between the control systems at different levels of the neuraxis ensure that locomotion adjusts to its environment and meets task demands. In this article, we describe and discuss the essential contribution of somatosensory feedback to locomotion. We start with a discussion of how biomechanical properties of the body affect somatosensory feedback. We follow with the different types of mechanoreceptors and somatosensory afferents and their activity during locomotion. We then describe central projections to locomotor networks and the modulation of somatosensory feedback during locomotion and its mechanisms. We then discuss experimental approaches and animal models used to investigate the control of locomotion by somatosensory feedback before providing an overview of the different functional roles of somatosensory feedback for locomotion. Lastly, we briefly describe the role of somatosensory feedback in the recovery of locomotion after neurological injury. We highlight the fact that somatosensory feedback is an essential component of a highly integrated system for locomotor control. © 2021 American Physiological Society. Compr Physiol 11:1-71, 2021.

New technologies applied to canine limb prostheses: A review

Although only a few studies have investigated about the development of animal prosthesis, currently, there is an increasing interest in canine limb prosthesis design and its clinical application since they offer an alternative to killing the animal in extreme situations where amputating the limb is the only option. Restoring normal function of amputated canine limbs with the use of a prosthesis is challenging. However, recent advances in surgical procedures and prosthesis design technology appear promising in developing devices that closely recreate normal canine limb function. Surgical advances such as evolution of osseointegration (bone-anchored) prostheses present great promise. Likewise, modern computer-aided design and manufacturing technology, as well as novel motion analysis systems are now providing improved prosthesis designs. Advances in patient-customized prostheses have the potential to reduce the risk of implant failure. The objective of this investigation is to present a general review of the existing literature on modern surgical approaches, design and manufacturing methods, as well as biomechanical analyses so that veterinarians can make more and better-informed decisions on the development and selection of proper canine limb prosthesis. Isolated research efforts have made possible an improvement in stability, comfort, and performance of canine limb prosthesis. However, continued multidisciplinary research collaboration and teamwork among veterinarians, engineers, designers, and industry, with supporting scientific evidence, is required to better understand the development of canine limb prosthesis designs that closely replicate the normal limb function.

Evaluation of Variability in Gait Styles Used by Dogs Completing Weave Poles in Agility Competition and Its Effect on Completion of the Obstacle

Objective: The aim of this study was to evaluate and define paw placement patterns for canines completing the weave pole obstacle during canine agility trials. The secondary objectives were to determine the most efficient running style and completion percentages and provide a basis for future studies to evaluate the long-term implications of variants in weave style and predisposition to injury. We hypothesized that dogs would display definitive gait patterns and that a single stepping pattern would yield faster run times compared to double stepping patterns. Animals: A total of 1,377 video recordings of dogs completing weaves poles at the American Kennel Club 2019 National Agility Championship were viewed. Procedures: Competition videos were reviewed as dogs attempted completion of the weave pole obstacle. Data collected included front limb and rear limb paw placement styles, time to complete the obstacle, and demographic data. Results: Attempts could be classified into one of five styles based on front and rear paw placement, with no one style dominant. Weave style differed by height and breed, with taller dogs and Border Collies preferring a single stepping style. Weave times were significantly faster for competitors using a single stepping style vs. other gaits. Conclusions and Clinical Relevance: This study found five identifiable gait styles used by dogs running weave pole obstacles, with front feet single stepping yielding significantly faster run times compared to other gaits. A clear classification of running styles will allow future studies to evaluate different stresses on joints, such as the shoulder, between varying gait styles, which could lead to recommendations for injury prevention.

Evaluation of Meniscal Load and Load Distribution in the Canine Stifle after Tibial Plateau Levelling Osteotomy with Postoperative Tibia Plateau Angles of 6 and 1 Degrees

OBJECTIVES

 The aim of the study was to investigate the kinetic and kinematic changes in the stifle after a tibial plateau levelling osteotomy (TPLO) with a postoperative tibia plateau angle (TPA) of either 6 or 1 degrees.

STUDY DESIGN

 Biomechanical ex vivo study using seven unpaired canine cadaver hindlimbs from adult Retrievers.Hinge plates were applied and a sham TPLO surgery was performed. Motion sensors were fixed to the tibia and the femur for kinematic data acquisition. Pressure mapping sensors were placed between femur and both menisci. Thirty per cent bodyweight was applied to the limbs with the stifle in 135 degrees of extension. Each knee was tested with intact cranial cruciate ligament (CCL), deficient CCL, 6 degrees TPLO and 1degree TPLO.

RESULTS

 Transection of the CCL altered kinematics and kinetics. However, comparing the intact with both TPLO set-ups, no changes in kinematics were detected. After 1 degree TPLO, a significant reduction in the force acting on both menisci was detected (p = 0.006).

CONCLUSIONS

 Tibial plateau levelling osteotomy restores stifle kinematics and meniscal kinetics after transection of the CCL ex vivo. The contact force on both menisci is reduced significantly after TPLO with a TPA of 1 degree. Increased stifle flexion might lead to caudal tibial motion.

Biomechanics of the Canine Elbow Joint

The canine elbow joint is a complex joint, whose musculoskeletal anatomy is well investigated. During the last 30 years kinematic analysis has gained importance in veterinary research and kinematics of the healthy and medial coronoid disease affected canine elbow joint are progressively investigated. Video-kinematographic analysis represents the most commonly used technique and multiple studies have investigated the range of motion, angular velocity, duration of swing and stance phase, stride length and other kinematic parameters, mostly in the sagittal plane only. However, this technique is more error-prone and data gained by video-kinematography represent the kinematics of the whole limb including the soft tissue envelope. A more precise evaluation of the in vivo bone and joint movement can only been achieved using fluoroscopic kinematography. Based on recent studies significant differences in the motion pattern between healthy joints and elbows with medial coronoid disease could be detected. Thereby not only adaptive changes, caused by pain and lameness, could be described, but primary changes in the micromotion of the joint forming bones could be found, which potentially represent new factors in the pathogenesis of medial coronoid disease. This chapter gives a review of current literature on elbow joint kinematics, with particular focus onto pathologic biomechanics in dysplastic canine elbows.

Three-Dimensional Kinematic Motion of the Craniocervical Junction of Chihuahuas and Labrador Retrievers

All vertebrate species have a distinct morphology and movement pattern, which reflect the adaption of the animal to its habitat. Yet, our knowledge of motion patterns of the craniocervical junction of dogs is very limited. The aim of this prospective study is to perform a detailed analysis and description of three-dimensional craniocervical motion during locomotion in clinically sound Chihuahuas and Labrador retrievers. This study presents the first in vivo recorded motions of the craniocervical junction of clinically sound Chihuahuas (n = 8) and clinically sound Labrador retrievers (n = 3) using biplanar fluoroscopy. Scientific rotoscoping was used to reconstruct three-dimensional kinematics during locomotion. The same basic motion patterns were found in Chihuahuas and Labrador retrievers during walking. Sagittal, lateral, and axial rotation could be observed in both the atlantoaxial and the atlantooccipital joints during head motion and locomotion. Lateral and axial rotation occurred as a coupled motion pattern. The amplitudes of axial and lateral rotation of the total upper cervical motion and the atlantoaxial joint were higher in Labrador retrievers than in Chihuahuas. The range of motion (ROM) maxima were 20°, 26°, and 24° in the sagittal, lateral, and axial planes, respectively, of the atlantoaxial joint. ROM maxima of 30°, 16°, and 18° in the sagittal, lateral, and axial planes, respectively, were found at the atlantooccipital joint. The average absolute sagittal rotation of the atlas was slightly higher in Chihuahuas (between 9.1 ± 6.8° and 18.7 ± 9.9°) as compared with that of Labrador retrievers (between 5.7 ± 4.6° and 14.5 ± 2.6°), which corresponds to the more acute angle of the atlas in Chihuahuas. Individual differences for example, varying in amplitude or time of occurrence are reported.

A Comparison of Two-Dimensional and Three-Dimensional Techniques for Kinematic Analysis of the Sagittal Motion of Sheep Hindlimbs During Walking on a Treadmill

Compared to rodents, sheep offer several attractive features as an experimental model for testing different medical and surgical interventions related to pathological gait caused by neurological diseases and injuries. To use sheep for development of novel treatment strategies in the field of neuroscience, it is key to establish the relevant kinematic features of locomotion in this species. To use sheep for development of novel treatment strategies in the field of neuroscience, it is crucial to understand fundamental baseline characteristics of locomotion in this species. Despite their relevance for medical research, little is known about the locomotion in the ovine model, and next to nothing about the three-dimensional (3D) kinematics of the hindlimb. This study is the first to perform and compare two-dimensional (2D) and 3D hindlimb kinematics of the sagittal motion during treadmill walking in the ovine model. Our results show that the most significant differences took place throughout the swing phase of the gait cycle were for the distal joints, ankle and metatarsophalangeal joint, whereas the hip and knee joints were much less affected. The results provide evidence of the inadequacy of a 2D approach to the computation of joint kinematics in clinically normal sheep during treadmill walking when the interest is centered on the hoof's joints. The findings from the present investigation are likely to be useful for an accurate, quantitative and objective assessment of functionally altered gait and its underlying neuronal mechanisms and biomechanical consequences.

Development of a three-dimensional computer model of the canine pelvic limb including cruciate ligaments to simulate movement

Gait analysis as subjective visual assessment forms the foundation of the veterinarian's lameness examination. Pelvic limb lameness is frequently seen in dogs and the stifle joint with its cruciate ligaments, is a main cause of lameness due to cruciate ligament deficiency. In this study, we developed an open-source three-dimensional musculoskeletal pelvic limb model of a 30 kg Labrador Retriever including cruciate ligaments, simulating the gait cycle of the walking movement with the open-source programs NMSBuilder (Institutio Ortopedico Rizzoli, Bologna, Italy) and OpenSim (National Center for Simulation in Rehabilitation Research (NCSRR), Stanford, CA, USA). The computer model generated muscle activations based on motion data. The computed activations were similar to experimental electromyogram data. Highest joint torque was in extension/flexion in the stifle joint at 54 Nm at 14% of the gait cycle with cruciate ligaments. Highest stifle joint reaction force was 408 N at 16% of the gait cycle and was reduced after adding cruciate ligaments. Especially the cranial cruciate ligament loads up to 102 N (34% body weight). Cranial cruciate ligament forces increase with stifle extension and decrease with stifle flexion. On the contrary, the caudal cruciate ligament loads up to 27 N (9% body weight) during the swing phase with a flexed stifle joint. The model was validated with electromyogram data. The model's predictions are plausible because joint torques and forces match the applied ground reaction forces in curve progression and in timing. This model forms a basis for further investigations into stifle surgery after cruciate ligament deficiency.

Three-dimensional motion of the patella in French bulldogs with and without medial patellar luxation

Background

French bulldogs exhibit significantly larger femoral external rotation and abduction than other breeds. We were curious as to whether this peculiar leg kinematic affects patellar motion and/or might induce medial patellar subluxation (MPSL) or medial patellar permanent luxation (MPPL). We hypothesized that the more abducted leg posture during stance causes an unusual medial pull direction of the rectus femoris muscle during stance, and that this may facilitate the occurrence of MPSL or even MPPL during locomotion. To test our hypothesis, we analyzed existing stifle-joint X-ray-sequences collected during the treadmill walk and trot of seven adult female French bulldogs. We estimated 3D-patellar kinematics using Scientific Rotoscoping.

Results

The three-dimensional motion of the patella comprises rotations and translations. From the seven dogs analyzed, three exhibited MPSL and one MPPL during the gait cycle. Medial patellar luxation (MPL) occurred mostly around toe-off in both gaits studied.

Patellar position was generally not gait-related at the analyzed timepoints. In dogs with MPL, the patella was placed significantly more distally (p = 0.037) at touch-down (TD) and at midswing (p = 0.024), and significantly more medial at midswing (p = 0.045) compared to dogs without MPL.

Conclusions

Medial patellar luxation seems to be the consequence of the far from parasagittal position of the stifle joint during stance due to a broad trunk, and a wide pelvis. This peculiar leg orientation leads to a medial sideway pull caused by the rectus femoris muscle and the quadriceps femoris and may initiate plastic deformation of the growing femur and tibia. Thus, a way to avoid MPL could be to control breeding by selecting dogs with lean bodies and narrow pelvis. Actual breeding control programs based on the orthopedic examination are susceptible to errors. Systematic errors arise from the fact that the grading system is highly dependent on the dog’s condition and the veterinarians’ ability to perform the palpation on the stifle. Based on our results, the position of the patella at TD, or even perhaps during stand might offer a possibility of an objective radioscopic diagnostic of the MPL.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12917-021-02787-z.

Comparative anatomy and morphology of the knee in translational models for articular cartilage disorders. Part I: Large animals

BACKGROUND

The human knee is a complex joint, and affected by a variety of articular cartilage disorders. Large animal models are critical to model the complex disease mechanisms affecting a functional joint. Species-dependent differences highly affect the results of a pre-clinical study and need to be considered, necessitating specific knowledge not only of macroscopic and microscopic anatomical and pathological aspects, but also characteristics of their individual gait and joint movements.

METHODS

Literature search in Pubmed.

RESULTS AND DISCUSSION

This narrative review summarizes the most relevant anatomical structural and functional characteristics of the knee (stifle) joints of the major translational large animal species, comprising dogs, (mini)pigs, sheep, goats, and horses in comparison with humans. Specific characteristics of each species, including kinematical gait parameters are provided. Considering these multifactorial dimensions will allow to select the appropriate model for answering the research questions in a clinically relevant fashion.

Functional assessment of the gluteus medius, cranial part of the biceps femoris, and vastus lateralis in Beagle dogs based on a novel gait phase classification

In humans, walking analysis based on the gait phase classification has been used for interpretation of functional roles of different movements occurring at individual joints, and it is useful for establishing a rehabilitation plan. However, there have been few reports on canine gait phase classification, and this is one of the reasons for preventing progress in canine rehabilitation. In this study, we determined phases of the canine gait cycle (GC) on the basis of the phase classification for human gait. The canine GC was able to be divided into initial contact (IC) and the following 5 phases: loading response (LR), middle stance (MidSt), pre-swing (PSw), early swing (ESw), and late swing (LSw). Next, the hind limb joint angles of the hip, stifle and tarsal joints and results of surface electromyography of the gluteus medius (GM), cranial part of the biceps femoris (CBF) and vastus lateralis (VL) muscles in relation to the gait phases were analyzed. The activities of three muscles showed similar changes during walking. The muscle activities were high in the LR phase and then declined and reached a minimum in the PSw phase, but they increased and reached a peak in the LSw phase, which was followed by the LR phase. In conclusion, the multiphasic canine GC was developed by modification of the human model, and the GC phase-related changes in the muscle activity and joint angles suggested the functions of GM, CBF and VL muscles in walking.

A Practical Guide to Measuring Ex vivo Joint Mobility Using XROMM

X-Ray Reconstruction of Moving Morphology (XROMM), though traditionally used for studies of in vivo skeletal kinematics, can also be used to precisely and accurately measure ex vivo range of motion from cadaveric manipulations. The workflow for these studies is holistically similar to the in vivo XROMM workflow but presents several unique challenges. This paper aims to serve as a practical guide by walking through each step of the ex vivo XROMM process: how to acquire and prepare cadaveric specimens, how to manipulate specimens to collect X-ray data, and how to use these data to compute joint rotational mobility. Along the way, it offers recommendations for best practices and for avoiding common pitfalls to ensure a successful study.

Working Dog Structure: Evaluation and Relationship to Function

Working dogs help to keep society and individuals safe, secure, and healthy. To perform their varied functions, it is critical to select dogs that are structurally sound and capable of demonstrating power, coordination and agility. Characteristics such as size and substance, head and axial skeletal structure, chest size and conformation, and thoracic and pelvic limb angulation should be evaluated to select the optimal combination of characteristics to suit the tasks to which each dog will be assigned. This review provides guidance on how to evaluate each of these structural components and discusses the contributions of those body parts to a working dog's function.

Review of kinematic analysis in dogs

Objective gait analysis techniques aid investigators in the study of motion. Kinematic gait analysis techniques that objectively quantitate motion are valuable tools used to understand normal and abnormal motion in domestic animals. Recent advances in video technology have made the study of motion more readily accessible. Available systems can document gait in two or three dimensions (2D or 3D, respectively). Knowledge of fundamental gait analysis concepts is critical to generating meaningful data. The objective of this report is to review principles of kinematic data collection and analyses, with a focus on differences between 2D and 3D systems.

Impact of wearing a service vest on three-dimensional truncal motion in dogs

OBJECTIVE

To develop a 3-D kinematic model to measure truncal motion in dogs and assess changes in truncal motion in dogs when wearing each of 2 service vests.

ANIMALS

5 adult mixed-breed dogs.

PROCEDURES

27 reflective markers were placed on the pelvis, trunk, and scapula of each dog. Six infrared cameras were placed around a treadmill to track the location of the markers within a calibrated space. Dogs were recorded during walking and trotting on the treadmill. Local and global coordinate systems were established, and a segmental rigid-body model of the trunk was created. Dogs were then recorded while wearing a custom vest and an adjustable vest during walking and trotting on the treadmill. Range of motion of the trunk when dogs were and were not wearing vests was compared by repeated-measures ANOVA.

RESULTS

An anatomic coordinate system was established by use of markers located at T1, T13, and the xiphoid process. Range of motion of the trunk during a gait cycle did not differ significantly regardless of the day of the test for both walking and trotting gaits. Trunk motion of dogs when walking and trotting was significantly reduced when dogs were wearing a vest, compared with trunk motion when not wearing a vest.

CONCLUSIONS AND CLINICAL RELEVANCE

A 3-D kinematic model for measuring truncal rotation was developed. Results indicated measurable differences in the gait of dogs when wearing each of the 2 service vests, compared with the gait when not wearing a vest.

Description of soft tissue artifacts and related consequences on hindlimb kinematics during canine gait

Background

Soft tissue artifacts (STAs) are a source of error in marker-based gait analysis in dogs. While some studies have revealed the existence of STAs in the canine hindlimb, STAs and their influence on kinematic gait analysis remain unclear.

Methods

Thirteen healthy Taiwan dogs affixed with twenty skin markers on the thigh and crus were recruited. Soft tissue artifacts and their influence on the determination of segment poses and stifle angles were assessed by simultaneously measuring marker trajectories and kinematics of the underlying bones via a model-based fluoroscopic analysis method.

Results

Markers on the thigh showed higher STAs than those on the crus, with root-mean-square amplitudes up to 15.5 mm. None of the tested marker clusters were able to accurately reproduce the skeletal poses, in which the maximum root-mean-square deviations ranged from 3.4° to 8.1°. The use of markers resulted in overestimated stifle flexion during 40–60% of the gait cycle and underestimated stifle flexion during 80–90% of the gait cycle.

Conclusions

Considerable magnitudes and effects of STAs on the marker-based 3D gait analysis of dogs were demonstrated. The results indicate that the development of error-compensation techniques based on knowledge regarding STAs is warranted for more accurate gait analysis.

Evaluation of a multibody kinematics optimization method for three-dimensional canine pelvic limb gait analysis

BACKGROUND

Skin marker-based three-dimensional kinematic gait analysis were commonly used to assess the functional performance and movement biomechanics of the pelvic limb in dogs. Unfortunately, soft tissue artefact would compromise the accuracy of the reproduced pelvic limb kinematics. Multibody kinematics optimization framework was often employed to compensate the soft tissue artefact for a more accurate description of human joint kinematics, but its performance on the determination of canine pelvic limb skeletal kinematics has never been evaluated. This study aimed to evaluate a multibody kinematics optimization framework used for the determination of canine pelvic limb kinematics during gait by comparing its results to those obtained using computed tomography model-based fluoroscopy analysis.

RESULTS

Eight clinically normal dogs were enrolled in the study. Fluoroscopy videos of the stifle joint and skin marker trajectories were acquired when the dogs walked on a treadmill. The pelvic limb kinematics were reconstructed through marker-based multibody kinematics optimization and single-body optimization. The reference kinematics data were derived via a model-based fluoroscopy analysis. The use of multibody kinematics optimization yielded a significantly more accurate estimation of flexion/extension of the hip and stifle joints than the use of single-body optimization. The accuracy of the joint model parameters and the weightings to individual markers both influenced the soft tissue artefact compensation capability.

CONCLUSIONS

Multibody kinematics optimization designated for soft tissue artefact compensation was established and evaluated for its performance on canine gait analysis, which provided a further step in more accurately describing sagittal plane kinematics of the hip and stifle joints.